Mysterious genes

Peculiarities of the origin of hereditary diseases have been actively studied only in the XX century due to the successes in the field of genetics - science on heredity and variability. Most often the first clinical manifestations of hereditary diseases are detected in early childhood. Therefore, the children's doctor especially should know regularities and the mechanism of transmission of hereditary traits. This is necessary to address many theoretical and practical issues of its work.
It is known that the transfer of hereditary properties associated with a special filamentary structures cell chromosomes - carriers of genetic information. The main chemical component of a chromosome is a DNA - deoxyribonucleic acid. Study its structure and properties made it possible to understand the mechanisms and regularities of recording and playback of genetic information. So DNA is the material basis of heredity in the cell. Plot of chromosomes (DNA), which defines any symptom or group of symptoms in the body, called the genome. The set of all genes of an organism - genotype. The combination of all features of the organism, manifested throughout life, is a phenotype. Hereditary diseases occur, as a rule, due to changes in the genetic code. This so-called mutations. Mutations can be caused by environmental factors (ionizing radiation, some of biologically active chemical compounds, or occur naturally under the influence of various changes in the life of the cell and the organism as a whole.
The achievements of genetics has had a tremendous impact on the development of medicine. The data of molecular genetics has contributed to the transition to a new level of research in the study of individual development - embryology, age morphology and physiology, gerontology (the science of aging of an organism), and also research in the field of obstetrics, Pediatrics and other sections of clinical medicine. The old question about the role of heredity and environmental factors in the formation and development of the organism after years of considerable controversy, debate and confusion was resolved in the end, on the basis of recognition of the unity of genetic and environmental factors. In the process of development of each organism realization of a genetic program in the properties and characteristics of the new body is under the influence of others, the body of the conditions of existence. Genetic program provides inheritance body signs ancestors, its specific features, and the influence of the conditions of existence in the period of development of the organism determines the deviation of individual differences.
Will talk briefly about some hereditary diseases.
Chromosome diseases are characterized by the change in the structure and number of chromosomes. Prevalence among newborns is about 1%. Gross violations (anomalies) chromosomes incompatible with life. They frequent cause birth to a dead child.
Now of great concern to the pediatrician cause of inherited metabolic diseases that occur more frequently and vary within. Some of them may occur at birth, but many, and in a later period. Long flowing, they no clinically manifest.
Research in the field of biochemistry show that the metabolic processes in the cell are under dual control. On the one hand, this is nervous and endocrine regulation to ensure harmonization of metabolic processes with the terms of the environment of the cell, on the other - a complex system of genetic control of the enzyme protein synthesis. We can assume that the mutation of a gene is accompanied by a violation of the synthesis of the enzyme no matter in what part of a protein molecule occurs defect.
The absence or low level of activity of enzymes in most cases leads to the appearance of hereditary metabolic diseases - the so-called enzymopathies.
The first clinical manifestations of hereditary metabolic diseases in most cases are detected in early childhood. However, there are cases when hereditary pathology appears for the first time and adults. One of the most important methods for the study of hereditary diseases is a clinical-genealogical. It is based on a compilation of pedigrees patients.
Great value for studying the patterns of the inheritance of various characteristics, has a "twin"method. As you know, the twins can develop from a single fertilised egg (identical twins) or two fertilized at the same time oocytes (dayzetia twins). Identical twins are characterized by absolute similarity (identity) of the genotype and the similarity of the external characteristics (phenotype). Twin method gets the further development of not only the study of the laws of inheritance of many diseases, but also for clarification of the role of genetic predisposition.
It is believed that the body is about 2,000 enzymes involved in metabolism and theoretically deficit of one enzyme will give about 2,000 diseases. And if the deficit even in two or three enzymes, the number of hereditary diseases will increase. What they have known? Described? No. It is known only about 500 diseases exchange. The rest should be open, to describe, to study. A vast field of activity for many decades.
And another very important circumstance. The disease must be diagnosed in the period, while the level of unwanted toxins" (metabolites), accruing as a result of the absence of the enzyme will reach a level at which they start to show undesirable action.
Pediatrics and genetics... a Huge field work revealed to those who decide to devote himself to unravel the mysteries of hereditary diseases.